Hi, Jim
Well, Maxwell's "W2DU" balu ns are ferrite sleeve baluns and you can get those that go down to 160m. It's a matter of choosine the right ferrite for the frequenc;y range of interest, and using enough ferrite to build p the common-mode impedance! 73, Charlie, K4OTV From: James Rodenkirch [mailto:rodenkirch_...@msn.com] Sent: Saturday, February 15, 2014 11:45 AM To: Charlie Cunningham; 'Carl'; Top Band Contesting Subject: RE: Topband: Palomar R-X Noise Bridge Carl: I've read, at several places, that sleeve baluns are effective at VHF and above but not at HF frequencies..thoughts?? 72/73, Jim Rodenkirch --- former Tempest inspector for the U.S. Navy..ahhhhh...Tempest comcerns - the good 'ol days hi Hi! > From: charlie-cunning...@nc.rr.com > To: k...@jeremy.mv.com; topband@contesting.com > Date: Sat, 15 Feb 2014 11:39:14 -0500 > Subject: Re: Topband: Palomar R-X Noise Bridge > > I'm a great believer in ferrite sleeve baluns, Carl! That's all that I use, > and with a little work you can even connect two of them for 4:1 nalance. > > 73, > Charlie, K4OTV > > -----Original Message----- > From: Carl [mailto:k...@jeremy.mv.com] > Sent: Saturday, February 15, 2014 11:05 AM > To: Charlie Cunningham; 'TopBand' > Subject: Re: Topband: Palomar R-X Noise Bridge > > The lowest loss cable I have here is 75 Ohm 1" General Cable Fused Disc; its > > under a differnt name these days. Mostly air with poly discs and used for > the 200' runs for 10M, 2M, and 222 MHz. > > For the 160/80 inverted vee it is 450' of regular foamed 3/4" 75 Ohm CATV > hardline with a RG-11 jumper and plenty of ferrite to the feed point. Ive > been using ferrite sleeve baluns since the mid 70's; I was introduced to > them by the company I worked for who was building equipment for the joint > CIA/DOD Tempest program. > > Carl > KM1H > > > ----- Original Message ----- > From: "Charlie Cunningham" <charlie-cunning...@nc.rr.com> > To: <j...@audiosystemsgroup.com>; "'TopBand'" <topband@contesting.com> > Sent: Friday, February 14, 2014 10:00 PM > Subject: Re: Topband: Palomar R-X Noise Bridge > > > > All generally true, I expect, but I also believe that dielectric constant > > and dielectric losses also figure in and the lowest loss lines would be > > filled with air, dry nitrogen or evacuated. I expect those would likely be > > the lowest loss AND highest velocity factor cases. > > > > 73, > > Charlie, K4OTV > > > > -----Original Message----- > > From: Topband [mailto:topband-boun...@contesting.com] On Behalf Of Jim > > Brown > > Sent: Friday, February 14, 2014 9:42 PM > > To: 'TopBand' > > Subject: Re: Topband: Palomar R-X Noise Bridge > > > > On 2/14/2014 2:17 PM, Carl wrote: > >> Isnt that what "lowest loss" means? At least that was my intention. > > > > I must not have written clearly enough. I was not questioning the low > > loss, only that the high Vf was the way to get it. > > > > You DO get the low loss by going to larger coax, (like the 7/8-in hard > > line), but it's the fact that it's LARGER and has lower RF resistance, > > NOT the higher Vf. > > > > Think of it this way -- The higher Vf cable has less attenuation per ft > > because the higher Vf allows the center conductor to be larger. > > But a stub made with foam coax with Vf = 0.84 must be 27% longer than > > one with with a solid dielectric and Vf =.66. If those coaxes are the > > same diameter and of comparable quality, the stub attenuation and Q will > > be nearly the same. > > > > 73, Jim K9YC > > _________________ > > Topband Reflector Archives - http://www.contesting.com/_topband > > > > _________________ > > Topband Reflector Archives - http://www.contesting.com/_topband > > > > > > ----- > > No virus found in this message. > > Checked by AVG - www.avg.com > > Version: 2014.0.4259 / Virus Database: 3705/7095 - Release Date: 02/15/14 > > > > _________________ > Topband Reflector Archives - http://www.contesting.com/_topband _________________ Topband Reflector Archives - http://www.contesting.com/_topband